Atchison Topeka & Santa Fe Engine 2926 was one of 30 oil-burning Northern 4-8-4 P2900
Class steam locomotives built by the Baldwin Locomotive Works in Eddystone, just south
of Philadelphia, Pennsylvania, between 1943 and 1944. This engine received the builders
plate number 69814 and was placed in service on May 9, 1944.

AT&SF 2926 was in service until December 12, 1953. On October 29, 1956 the engine
and tender were donated to the City of Albuquerque, New Mexico and placed on display in
Coronado Park.

The Engine, Tender and Caboose were purchased by the New Mexico Steam Locomotive &
Railroad Historical Society from the City of Albuquerque on July 26, 1999 for eventual
restoration. That restoration is ongoing today and it is hoped that the engine will finally
be operational again in 3-5 years.

Q: How old is 2926?

A: Again, 2926 was originally built and placed in service on May 9th, 1944 which would make it 75 years old today.

Q: How big is 2926?

A: That depends on what you mean by big. Together, the engine and tender are
approximately 121 ft long.

A: Oil is burned in the firebox to heat the water in the boiler and make steam.
The steam is piped to the cylinders to drive pistons back-and-forth. The pistons
are connected to the steel pins on drive wheels by rods. When the pistons move back
and forth the rods transmit that force to the drive wheels making them rotate

See some excellent animations by www.mekanizmalar.com
of how the internals of a Steam Locomotive work at the bottom of this page.

Q: How powerful is the 2926?

A: There are three measures of power: tractive effort, draw bar pull, and horsepower.

Tractive Effort: The starting tractive effort generated by the drive wheels
is listed in all company documents and specifications as 66,000 lbs. However,
that figure is thought to be little low. The real tractive effort when
starting is estimated to be closer to 70,000-74,000 lbs.

Draw bar Pull: The actual pull exerted at the tender coupler (and therefore
available to pull the train) ranges between 68,000-72,000 lbs. This is
based on test data obtained from a similar Santa Fe 4-8-4 (#3766). The
difference between estimated tractive effort and actual measured draw
bar pull is the amount of tractive effort (several thousand pounds) needed
to start the dead weight of the tender.

Horsepower: Horsepower varies with speed. Maximum horsepower is developed
between 35-65 mph. Testing showed draw bar horsepower (measured at the
coupler on the rear of the tender and available to pull the train) as
4,590 at 40 mph. The locomotive was actually producing more horsepower
(500-800 more), but some power is consumed moving the engine and tender
at that speed. As speed increases, more horsepower is needed for the engine
and tender just to maintain the higher speed, and less is available to
pull the train.

Q: How fast could 2926 go?

A: Nobody really knows. It was designed for
90 mph operation. That doesn't mean it couldn't go faster. It was upgraded
(as were all 2900 class engines) between 1946-48 with light weight roller
bearing rods to increase the design speed to 100 mph and in passenger
service there are lots of stories of speeds well over the century mark.
But documented runs in excess of 100 do not exist. This is because running
over 100 mph exceeded established speed limits and could get engineers
in trouble. However, when running late and with a head nod from management,
crews did exceed 100 mph and occasionally (if the stories of old timers
are to be believed) exceeded 110 mph. The locomotive's design, wheels,
rods, bearings, pistons, lubrication, etc. should have been capable of
the machinery speeds required to exceed 120 mph or more.

Thanks to Dr. S. Ersoy (www.mekanizmalar.com) for giving permission to
imbed the following YouTube animation which depicts how the internals of a Steam engine work. AT&SF 2926 works
fundamentally in the same fashion, not withstanding the fact there are subtle differences in our wheel arrangement,
exact plumbing, etc.

Be sure to also check out the interactive animation at WWW.MEKANIZMALAR.COM of the basic
Walschaerts Valve Gear
mechanism that is used in many steam locomotives.